Thermal insulation for buildings and other structures is available in the form of mats, batts, blankets and loose fill. Mats, batts and blankets are flexible products containing randomly oriented fibers bound together with a binder, and are generally prefabricated before being brought to a construction site and installed. In contrast, loose fill thermal insulation includes a large number of discrete fibers, flakes, powders, granules and/or nodules of various materials. The loose fill can be poured or blown into hollow walls or other empty spaces to provide a thermal barrier.
Because of cost-effectiveness, speed and ease of application, as well as thoroughness of coverage in both open and confined areas, the practice of using pneumatically delivered or “blown” loose-fill insulation materials, e.g., glass fiber, rock wool, mineral fiber wool, cellulose fibers, expanded mica, and the like, has become an increasingly popular method by which to install insulation in new and existing building constructions.
Loose-fill insulation blown into attics, basements and outside wall cavities is very effective in reducing heat transfer in existing buildings. Loose-fill insulation can provide a substantial advantage over batt-type insulation in that the loose-fill material readily assumes the actual shape of the interior cavity being filled, whereas the insulative batts are manufactured in a limited number of standard size widths, none of which will as closely match the actual dimensions of wall cavities or accommodate obstructions encountered in the field. Properly installed, loose-fill insulation essentially completely fills a desired area of the building cavity, conforming to the actual shape of the building cavity, including obstructions, such as water, waste and gas lines, electrical conduits, and heating and air conditioning ducts, and provides, in that respect, effective resistance to heat transfer through walls, floors or ceilings.
Any insulation that is capable of compression has an expanded volume due to included air, within spaced apart, fibers or particles or foam of materials such as glass, polymer or cellulose. An industry standard R-value is a rating number that is printed on the insulation. The R-value refers to the extent to which the insulation reduces the rate of heat transfer through the insulation. The R-value typically increases with increases in thickness and with increases in density of the insulation for a given material. When the insulation is installed, it is capable of compression to fill a building cavity having a width, for example, on 12 inch centers, 16 inch centers, 17.7 inches or 24 inch centers. Further, the insulation is capable of compression to fill the cavity having a length defined by the width of either 9.5 inches for a 2×10 joist, or 11.5 inches for a 2×12 joist, or 13.5 inches for a 2×14 joist, or 15.5 inches for a 2×16 joist. Such a compression is in a direction transverse to the R-value and thickness, which would not substantially reduce the R-value of the insulation.
While insulation products based upon glass fibers are known, there is still a need to improve the thermal efficiency, “R”, of such products in a cost effective manner.